Multiple fuel carburetor



May 18, 1937. F. MADARIAGA 2,030,617

MULTIPLE FUEL CARBURETOR Filed June 10, 1935 2 Sheets-Sheet 1 INVENTOR.

m 07a at? a BY rfi I ATTORNEYS May 18, F MADARlAGA MULTIPLE FUEL CARBURETOR Filed June 10, 1955 2 sheets-sheet 2 INVENTOR.

ZZ BY v 6 644/ 4 ATTORNEYS Patented May 18, 1937 Q UNITED STATES PATENT OFFICE 2,080,617 MULTIPLE FUEL OARBURETOR Flavio Madariaga, Venice, Calif.

Application June 10, 1935, Serial No. 25,796 Claims. (01. act-1s) My invention relates to carburetors, and has carburetor adapted to supply gasoline to an inparticular reference to a carburetor adapted to e nal ombust on engine and adapted to pp y supply fuel of more than one character to intera low grade fuel to the engine in which the supply n'al combustion engines. of one type of fuel may be cut off and the other 5 In the operation of automobiles or ther 19- turned on alternately with the additional fea- 5 vices deriving their power from internal combusu e t at dep of Which fuel is being D- tion engines, it has been the practice to provide p ed o e engine the idling 0f the g e Wi l a carburetor for supplying th engine th a likewise occur upon the gasoline or similar mixture of air and gasified fuel, such as gasoreadily VolatiliZed flleiline, the carb ret being adjusted t t t Another object of the invention 1s to provide 10 lar character of fuel which is t v used in the a carburetor of the character set forth wherein engine during the normal operation of the engine with Various attempts have been made to operate low grade fuel acceleration of the engine y internal combustion engines of t t t be accomplished by supplyinga determined quan- 5 gasoline or similar readily volatilized fuels durtity of gasoline readily voiatiiized fuel at f ing the initial starting of the engine, while other instant acceleration is Occurring When P i low grade fu ls h b supplied to an engine hard. This also eliminates the knocking WhlCh after it has been sufiiciently heated tocause such Occurs with the low grade fuel when under lower grade fuels to volatilize sufficiently to perioeds by giving a richer mixture and by letting mit them to operate in the engine. in the h 20 Heretofore any attempts to Supply low grade Another object of the lnvention is to provide a,

' fuels through the ordinary gasoline carburetor carburetor which may supply either gasoline of the vehicle have met with but limited success, lower grade f l to an engine in which, independprimarily due to th fact t t was either ent of the character of the fuel being supplied to n3 essary to adjust the carburetor each time the the engine at any time, iihe engine Wiiibe Supplied change was made from gasoline to the lower with gasoline for idling Purposes and will he grade fuel a d due t t fact that during the plied with a determined amount acceleration operation of th engine on the low grade fuel the charge of more gasoline whenever acceleration idling fuel supplied to the engine, being of the is to occuhhr when under a heavyioad- 39 l grade Character, was not a properly Other objects and advantages will be apparent bustible mixture and therefore caused loading f a Study of following Specifications, readup of the engine because of the drop in tempera 1h coimectiorr with the accompanying drawings, ture and compression pressures at idling speed wherein with a mixture which was either too rich to be Figure 1 is a plan w of a f e readily burned in the engine, or was too lean to meted i accordance With my invention; keep the en ine idli Figure 2 is a sectional view, taken along line Again, a further disadvantage in the previous IIII of 11 methods of operating engines alternately on gas- Figure 3 is a Sectional View, taken along line oline and a lower grade fuel or on two grades of IHIII of 1? 40 gasoline, lay in the fact that when it was deure 4 is a sectional view, taken along line 40 sired to change the speed of the engine the low of 1; grade fuel did not respond with suiiicient rapidity ure 5 is a detail horizontal sectional view, tov prevent overloading of the engine, or, if the taken along e V of i e carburetor was adjusted to prevent this over- Figure 6 is a detail view, taken al g ne loading upon a sudden open throttle condition, of Figure and v at the instant of the opening of the throttle for Figure '7 is a detail, horizontal, sectional view gasoline purposes insufl'lcient fuel was supplied taken along line VIP-VII of Figure to the engine to cause it to readily accelerate. Referring o e drawings. I have illustrated It is an object of.my invention to provide a y u etor as Comprising a dy memher i carburetor which is adapted to supply either gashaving n ai passage [formed e AI! 50 oline or a low grade fuel or a lower grade of gaspassage 2 preferably extends from an air intake oline to the internal combustion engine with a Opening 3, formed upon a tubular boss extending minimum of necessary adjustment during the from one side of the body I, to an inlet manifold change from one fuel to the other. 4 formed upon a vertically extending tubular ex- Another object of the invention is to provide a tension 5 on the body member Thus the air 55 passage 2 extends at right angles through the body of the carburetor. Immediately at the base of the tubular extension 5 I mount a pair of injectors or jets 6 and 1, one of these jets 6 being adjusted for supplying gasoline or similar readily volatilized fuel to the air passage 2, while the other jet 1 is adapted and adjusted to supply the lower grade fuel to the air passage 2.

By referring particularly to Figs. 1 and 2, it will be observed that the jet 6 comprises an outer tubular member 8 suitably fixed in a threaded opening 9 in the body l of the carburetor, the lower end of the tubular member 8 being closed by a suitable plug l0. Spaced upwardly from the plug I 0 and threaded or otherwise secured within the tubular member 8 is an inner tube ll having a small bore l2 extending longitudinally therethrough, the member ll, terminating immediately below the outlet l3 of the outer tubular member 8. The bore communicates with a gasoline passage H by reason of a plurality of holes or openings I5 formed in the lower end of the tubular member 8. The gasoline passage I4 communicates with a suitable gasolin e reservoir or float chamber H5 in which any suitable type of float i! may be provided for the purpose of maintaining a supply of gasoline within the reservoir I6 at a predetermined level. With the apparatus thus far described it will be apparent that the passage of air through the intake opening 3 and through the air passage 2 upwardly into the intake manifold of the engine will cause a vacuum to be created immediately above the tubular member ll, causing gasoline to be drawn upwardly through the bore I2 and sprayed into the air passage 2 where it is mixed with the incoming air in suitable proportions depending upon the size of the bore I2 or other adjustment, which will be well-known to those skilled in the art, to provide a suitable fuel and air mixture adapted to operate the most efficiently with the particular engine to which the carburetor is adapted.

The apparatusthus far described is in all its essentials the usual type of carburetor mechanism employed for supplying internal combustion engines with gasoline fuel, the amount of the fuel mixture which is supplied to the engine being controlled by a suitable butterfly valve or throttle valve, l8 extending into the tubular extension 5 of the body member I and adapted to be moved to'various positions therein providing a variable opening in the air passage 2, as' is usual in carburetor construction and operation.

By referring particularly to Figures 1, 5, 6, and 7, it will be observed that in addition to the gasoline float chamber or reservoir I6 I provide a second reservoir or float chamber l8 which may be connected to any suitable source of supply for the lower grade fuel, such as kerosene, Diesel oil, or other low grade oils, or even a lower grade of gasoline, suitable for operation in internal combustion engines. The float chamber I9 is similar in all respects to the float chamber l8 previously described, the jet I being formed with a suitable outer tubular member 20 projecting upwardly into the air passage 2 and communicating through suitable openings 2| with a fuel passage 22 extending into communication with the float.

chamber llthrough which low grade fuel may pass. from the float chamber 19 to the air passage 2. Again it will be notedthat the jet 1 includes an 'inner tubular member 23 having a bore 24' which may be selected of such diameter and adjusted, as is well-known in the art, to supply the correct amount of low grade fuel to the air passage 2 to provide the most desirable complete combustible mixture of the low grade fuel and air.

By referring particularly to Figs. 2 and 7, it will be observed that the gasoline passage l4 and the fuel passage 22 extend substantially parallel to each other for a portion of their longitudinal extent, thus facilitating the interpositioning therein of a valve stem 25 having a pair of valve openings 26 and 21 extending therethrough at right angles to each other. Thus when the valve stem 25 is moved to one position, as indicated in Fig. 2, the passage ll for the gasoline will be opened, while the passage 22 for the low grade fuel will be closed and similarly, when the valve stem is moved to a position substantially at right angles to that illustrated in Fig. 2, the gasoline passage M will be closed, while the low grade fuel passage will be opened, thus providing a ready means by which the operator of the engine may select the fuel to be supplied to the air passage 2.

With the apparatus thus far described, it will be apparent that by the employment of the jets 6 and 7 each of these jets may be initially designed so as to supply the correct amounts of either fuel to the airpassage 2, so that when the change is to be made from the gasoline supply to low grade fuel, it is unnecessary to make any adjustments of the carburetor other than to merely operate the valve stem through an angle of It will also be understood by those skilled in' the art that other means may be employed for alternately supplying fuel to the air passage 2 from one or the other of the two jets 6 and that the illustrated embodiment incorporating the valve stem 6 is but one of many ways in which ,ing multiple fuels the change from one fuel to the other was a positive change making it necessary that the engine, once operating upon one fuel, must perform all of its operations upon this fuel until the next change over occurs to the other fuel at which time the engine was required to perform all of its operations upon this new fuel. However I provide means on my carburetor whereby, when the vehicleis operating upon gasoline, it may idle with a supply of gasoline fuel through the usual idling jet 28, commonly found upon gasoline carburetors. I also provide in my carburetor means whereby the engine, when being supplied with low grade fuel from the float chamber I! will also be supplied with gasoline for idling purposes through the idler jet 28. This is accomplished by providing a sump 29 inthe body I of the carburetor which sump communicates through a port 38 with'a secondary gasoline passage 8| communicating with the gasoline float chamber l8 and connecting the fuel pipe 32,

by which gasoline is supplied to the idling jet 28, with this sump 28. The port 30, by-which extending through a vertical bore 39 formed in the body of the carburetor. The upper part of the enlarged end 31 of the valve stem extends upwardly above the bushing 38 where it may be contacted by a piston 40 fitted within the bore 39. The piston 40 is provided with a piston stem 4| having a sliding fit in a tubular bushing 42 threaded into the upper end of the bore 39, the stem 4| being normally pressed downwardly by means of a relatively weak spring 43, the compression of which may be adjusted by a suitable adjusting screw 44. Near the upper end of the bore 39 I provide a passage 45 communicating with the air passage 2 of the carburetor, whereby vacuum created in the air passage 2 may be transmitted into the bore 39 to cause a lifting of the piston 40. The spring 34 should have sufficient strength to hold the valve 33 closed, except when the combined weight of the piston 49 and the compression of spring 43 is transmitted to the stem 35 at which time the valve 33 should open.

I also prefer to arrange the port or passage 45 directly in alignment with the edge of the butterfly valve I 8 when the butterfly valve is closed.

With the butterfly valve l8 closed, it will be apparent that a relatively high vacuum will be created in the upper end of air passage 2 above the butterfly valve 8 which will be effective to draw idling fuel through the pipe 32 and through the idling jet 28. However, since, when the butterfly valve |8 is closed, it closes the passage 45 vacuum will not be transmitted to the bore 39 and the piston 40 will be pressed by reason of its own weight, and also by reason of the spring 43 pressing downwardly upon the valve stem 35 to hold the valve 33 open to permit gasoline to pass from the gasoline passage 3| into the sump 29. Thus as long as the butterfly valve I8 is closed, (representing the idling position of the butterfly valve l8), a continuous supply of fuel is permitted to pass into the sump 29 from which it may be drawn through the pipe 32 to the idling jet 28.

It will also be noted at this point that the supply of gasoline to the sump 29 will occur independently of the position of the cutoff valve stem 25 so that whether the carburetor is operating upon gasoline supplied to the jet 6 or upon low grade fuel supplied to the jet 1, the idler jet 28 will always be supplied with gasoline, permitting the engine to idle on gasoline fuel during all of its idling periods. This arrangement of supplying gasoline for idling purposes even after the change-over has been made from gasoline to low grade fuel, insures against overloading of the engine with the low grade fuel and insures the steady idling of the engine and eliminates smoke.

It will be noted by those skilled in the art that while the low grade fuel may be supplied for the general operating conditions of the engine and thus permit the saving in the ordinary operation of the engine due to the employment of the low grade and cheaper fluids, the engine will idle on gasoline at all times, avoiding one of the primary difficulties to the use of multiple fuels encountered in previous attempts to use the lower grades of fuel for ordinary internal combustion engine operation.

As hereinbefore stated, difficulty has been encountered in operating a gasoline engine on the lower grade fuel during the acceleration periods of the engine, and also under heavy loads on account of pre-combustion. I find that by supplying a determined quantity of gasoline to the engine during the acceleration periods (also when under heavy loads) this difiiculty may be overcome and I permit the employment of the low grade fuels for the major portion of the operations of the engine with its attendant economy of fuel cost. I accomplish this by supplying a determined quantity of gasoline and by providing an auxiliary gasoline passage 46 communicating between the sump 29 and the tubular member 8 of the jet 6, and having a metering orifice 41 therein.

As will be understood by those skilled in the art, the manipulation of the butterfly valve I8 to rapidly accelerate the engine will be such as .to open the butterfly valve I8 relatively wide,

at which time substantially no vacuum will be present in the air passage 2, permitting the piston 40 to fall upon the valve stem 35 and open the valve 33, allowing a considerable quantity of gasoline to flow into the sump 29. As, the inrush of air through the intake opening 3 occurs, gasoline will be drawn from the sump 29 through the tubular member 8 to supply a small charge of gasoline to this air, in addition to such fuel as may also be supplied to the air through the jet 1. This small quantity of gasoline, or gasoline vapor, will permit the engine to rapidly pick up speed and once it attains the new speed the vacuum created in the air passage 2 will become sufficient to be transmitted through the port 45 to the piston 40, lifting the piston 40 and permitting the valve 33 to reclose. Thus further operation of the engine will empty the sump 29 and thereafter all of the engine operation will occur with the use of low grade fuel supplied directly through the jet 1. The supply of fuel through the auxiliary passage 46 will also occur whenever the motor is operating under heavy loads, such as when the vehicle is driven up a relatively steep grade, at which time the vacuum in the intake manifold and the air passage 2 will be reduced substantially to zero, permitting the valve 33 to open and supply gasoline into the sump 29. Under these conditions fuel from the sump 29 will be passed to the jet 8 and will add to, or enrich the combustible mixture passed to the engine. This arrangement avoids one of the objections to prior devices employing low grade fuels, since by this addition of similar quantities of gasoline to the mixture when the engine is operating under heavy loads, it avoids the knocking usually resulting.

In order to supply air to the sump 29, I provide an air passage 48 communicating directly with the sump.

It will be observed, therefore, that I have provided a variable fuel carburetor in which the engine may be started and warmed up with the use of gasoline as a fuel supplied directly through a gasoline jet in the carburetor especially adjusted for performance with gasoline fuel.

Thereafter the valve stem 25 may be operated to cut-off the main supply of gasoline to the jet 6 and permit the supply of low grade fuel to the jet 1, the engine then operating for the major portion of its operations directly and solely with the low grade fuel.

It will also be observed that during such times as it is desired to rapidly accelerate the engine the normal manipulation of the butterfly valve 3 for gasoline purposes will cause a small quantity of gasoline to be supplied in addition to the supply of low grade fuel assisting in the acceleration of the engine and preventing the usual smoking, choking and missing which ordinarily occurs during the rapid acceleration of an internal combustion engine using the low grade fuels.

It will be further observed that independent of whether the engine is operating with gasoline or with the low grade fuel, the manipulation of the butterfly valve to cause the engine to idle, will automatically cause the supplying of gasoline directly to the engine through the usual idling jet so that the idling of the engine will occur at all times with a supply of gasoline fuel, thus avoiding the usual disadvantages encountered whenever attempts have been made to idle an engine while supplying the same with low grade fuel.

It will also be observed that with my carburetor all of the operating conditions of the engine are automatically provided for it being unnecessary for the operator of the vehicle to manually adjust any of the mechanism except to change the position of the valve stem 25 when he desires to change over from one fuel to the other.

While I have shown and described the preferred embodiment of my invention, it is to be understood that I do not wish to be limited to any of the details of construction shown herein, except as defined in the appended claims.

I claim:

1. In a multiple fuel carburetor, means defining an air passage through which air and fuel may bepassed to an engine, a reservoir for one type of fuel, a second reservoir for a second type of fuel, a fuel passage intercommunicating said first reservoir and said air passage,-a second fuel passage intercommunicating said second reservoir and said air passage, means for alternately closing one or the other of said fuel passages, a sump, means for supplying fuel from said first reservoir to said sump, an idler jet, and means connecting said idler jet with said sump to supply idling fuel to said engine from said first reservoir independent of said first named fuel passage.

2. In a multiple fuel carburetor, means defin-- ing an air passage through which air and fuel may be passed to an engine, a reservoir for one type of fuel, a second reservoir for a second type of fuel, a fuel passage intercommunicating said first reservoir and said air passage, a second fuel passage intercommunicating said second reservoir and said air passage, means for alternately closing one or the other of said fuel passages, a sump, means for supplying fuel from said first reservoir to said sump, and an auxiliary fuel passage intercommunicating said sump with said air passage independently of said closing means.

"reservoir to' said sump, valve means interposed between'said first named reservoir and said sump, and means responsive to vacuum in said air passage for closing said valve when vacuum is present in said air passage.

4. In a multiple fuel carburetor for supplying fuel to an internal combustion engine, a reservoir for one type of fuel, a second reservoir for a second type of fuel, an air passage through which air is drawn through said carburetor into said engine, jet means extending into said airpas- I sage through which fuel from said reservoirs is projected into said air passage, a fuel passage leading from one of said reservoirs to said jet means, a second fuel passage leading from the other of said reservoirs to said jet means, means for alternately closing one or the other of said fuel passages, an auxiliary fuel passage leading from one of said reservoirs to said jet means, throttle means for controlling the flow of air through said air passage, and means responsive to the rapid opening of said throttle means for causing fuel to be supplied through said auxiliary fuel passage to said engine during acceleration of said engine.

5. In a multiple fuel carburetor for supplying fuel to an internal combustion engine, a reservoir for one type of fuel, a second reservoir for a second type of fuel, an air passage through which air is drawn through said carburetor into said engine, jet means extending into said air passage through which fuel from said reservoirs is projected into said air passage, a fuel passage leading from one of said reservoirs to said jet means, a second fuel passage leading from the other of said reservoirs to said jet means; means for alternately closing one or the other of said fuel passages, an auxiliary fuel passage leading from one of said reservoirs to said jet means, throttle means for controlling the flow of air through said passage, a

.throttle interposed in said auxiliary fuel passage between said reservoir and said-jet'means, and

-means responsive to any decrease in vacuum in said air passage when said throttle is .opened rapidly for opening said valve means to cause fuel to be supplied through said auxiliary fuel passage to said engine during acceleration. FLAVIO MADARIAGA. 

